I have to admit I always just use center point AF and then recompose.But there are moments thats far from ideal. So Im wondering if I have the multipoint activated exactly what does the camera prioratize? Just the point that has the shortest distance to the camera or what?

From my experience, it has almost always been the nearest point to the camera. Sometimes a higher conterast area than the nearest point attracts that AF point, but for the most part it's the closest point. I always use the center AF point unless tripod mounted.